The invention generally relates to a weight counterbalance means. More specifically, the invention relates to a weight counterbalance means for a two-jointed support arm. Yet more specifically, the invention relates to a weight counterbalance means for a bipartite bracket mechanism in an x-ray apparatus having first and second brackets (arm members), wherein one end of the first bracket is rotatably seated around a horizontal, first shaft at the base of the x-ray apparatus and the other end is rotatably connected via a second shaft to one end of the second bracket, the other end of which is secured to an x-ray tube.
A weight counterbalance means of the type to which the invention relates is disclosed by German published application 27 04 555, the teachings of which are incorporated herein by reference. In the disclosed apparatus, every bracket (arm member) is balanced out by an associated roller that is pressed by a spring against a cam plate associated with the bracket. In relationship to the rotational center of its respective cam plate, the force of each roller is directed such that a torque arises at the cam plate that serves to hold the torque acting on the bracket in equilibrium in every bracket position. Gear wheels and chains are employed as means for transmitting the motion between the cam plates and the respective shafts of the brackets.